Linux is doing, in a word, great.
There are several areas where Linux and open source software are doing great, especially in the new technologies where open source encourages innovation:
- Client/server shipment growth
- Client/server installed base growth
- Software/virtual appliances
- Cloud computing
- Clusters and supercomputers
When we look at Linux market growth on both the client and server, there is a solid history of uninterrupted growth, starting around 2001. Over time, the growth rates have dropped as Linux has matured and the number of shipments per year has increased.
On the client side, Linux continues to grow at a rate higher than Windows. Linux still has far less of the client market than Windows. The limiting factor for Linux, both client and server, is application availability. But, when compared to other operating systems, Linux is making great strides in application availability, especially on the server side. Novell and Red Hat now have well over 3,500 certified applications. In a paper titled UNIX: Wedged Between an x86 Rock and a Mainframe Hard Place, Gartner indicates that Linux (server side) is second to Windows in terms of number of certified applications and ISV enthusiasm. Solaris 10 has more applications, but it lags significantly in terms of ISV enthusiasm.
An interesting statistic, not usually broken out, is how Linux (paid) and Windows (paid) shipments are doing with respect to each other when only these two operating systems are considered. This statistic is calculated by determining the total number of Linux client plus Windows client shipments per year, then determining what percent of these shipments are Windows clients and what percent are Linux clients. From 2006 through 2012 (forecasts), Windows client shipments are dropping about 0.5% per year and Linux client shipments are growing more than 0.5% per year. On the server side, Windows server shipments are dropping more than 1% per year and Linux server shipments are increasing more than 1% per year. There are no fluctuations in the comparisons: it's a steady decline for Windows and a steady growth for Linux.
Another statistic that shows how well Linux is doing, again in a comparison with Windows, is with respect to share of worldwide server shipments by operating system. From 2005 with forecasts through 2012, the Windows share of the worldwide server shipments is essentially flat at around 70%; whereas Linux‚Äôs share of the worldwide server shipments shows steady growth of about 0.5% per year with a share exceeding 23% around 2012.
Combined Linux client and server new license (subscription) revenue is growing at a compound annual growth rate (CAGR) (2007-2012) of over 19%; whereas Windows client and server combined license revenue is growing at a CAGR of only 8.7%. When examined individually, Linux paid client shipments are growing at a CAGR of 15% and Windows client shipments are growing at a CAGR of only 8.9%. On the server side, paid Linux shipments are growing at a CAGR of 9.4% while Windows is growing at a CAGR of 7.9%.
Installed base statistics are always interesting to examine because they can allow you to predict when the Linux installed base will exceed the Windows installed base provided certain growth conditions hold. The Linux client installed base is growing at a CAGR (2007-2012) of 18.6%; whereas, Windows client installed base is growing at a 9.9% clip. Linux server installed base is growing at a 13.5% rate; whereas, Windows server installed base is growing at only 8.9%.
In terms of software appliances, IDC says that the rate of growth (CAGR) of shipments for paid Linux as the embedded operating system in software appliances is over 100%; whereas, for Windows it is 32.9%. Within two or three years, Linux is expected to emerge as the clear-cut, favored operating system for ISVs for building software/virtual appliances. Microsoft has indicated little interest in software appliances because its distribution channel is so closely tied to hardware, and Microsoft does not want to concede that all the hardware needs is a hypervisor to run applications. In addition, the delivery of software appliances with Windows as the embedded operating system would cost Microsoft some of the licensing revenue that it gains from selling full-blown Windows.
No virtualization software platform (or vendor) has been adopted as the de facto virtualization platform for cloud computing. But cloud computing is dominated by open source Xen and Linux. The reason: cloud providers do not want to pay stiff licensing fees. Even in those cases where cloud providers do not use the open source version of Xen, they are attracted to commercial versions of Xen such as Citrix XenServer, which is free. Commercial versions of Xen tend to have complementary software such as management software around them, reducing the work that cloud providers have to do to quickly get to the market. According to Tom Bittman, Gartner VP, Windows will not be a prominent player in public clouds, because cloud providers such as Amazon EC2 don‚Äôt care what the operating system is. All they care about is what services are being provided.
Amazon EC2 is run on open source Xen and Linux. Antonio Piraino, analyst at the 451 Group, says that big public clouds such as Amazon EC2 tend to run on Xen because it is free and open source. Other large public cloud enthusiasts such as Google, Cisco, and Verizon utilize Linux. Vendors such as VMware and Microsoft, with their price structures, are falling behind Linux and open source hypervisors in public clouds.
Since 2000, when IBM and SuSE teamed up to create Linux for the mainframe, Linux has dominated the market for non-IBM operating systems on the mainframe. Only recently has Solaris been ported to the mainframe. IBM says that nearly 5,000 IFLs (Integrated Facility for Linux) are being used to run Linux on the mainframe. Dozens of instances of Linux can run on a single IFL-specialty processor. Linux for the mainframe has become an important option for IT managers utilizing server virtualization to reduce costs.
Linux has been growing fast in clustering and supercomputers since the beginning of this decade. Linux now powers in excess of 85% of the world‚Äôs top 500 supercomputers. Linux is by far the operating system of choice and the product‚Äôs scalability, reliability, and integration capabilities with cluster architectures have made Linux skyrocket to dominate the world‚Äôs top 500 supercomputers. The first four systems in the Top500 list run Linux, with Linux deployed on nine of the top 10 supercomputers. By contrast, Microsoft Windows accounts for just 1% of the Top500 supercomputers, running on just five systems.
There are several other areas where Linux is thriving. It is replacing UNIX as the leading host for non-Microsoft database management systems and carrier grade systems. Linux and Windows are now the two dominant developer platforms. Linux is a leading competitor in the embedded systems world with companies such as Wind River.
Overall, Linux has maintained steady growth in a number of areas and dominates in some areas with Windows the primary competitor. The primary reasons for this growth and dominance are cost and innovation. Innovation is especially key because IT managers are always looking for new technologies and new ways to lower their costs and increase business agility. For the past several releases, about every two years, commercial Linux vendors have announced releases with new innovative technologies. On the other hand, Microsoft has struggled to release a new Windows operating system with little evidence of new technologies every four to five years.
This overview gives just the broadest sense of how Linux is faring in a variety of arenas, and it's clear the momentum is clearly on the side of the penguin in the years to come.